1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
pub unsafe trait InlineStorage{}
macro_rules! impl_for_arrays {
( ty=$ty:ty , len[ $($len:expr),* $(,)* ] ) => (
$(
unsafe impl InlineStorage for [$ty;$len] {}
)*
)
}
impl_for_arrays!{
ty=u8,
len[
0,1,2,3,4,5,6,7,8,9,
10,11,12,13,14,15,16,17,18,19,
20,21,22,23,24,25,26,27,28,29,
30,31,32,33,34,35,36,37,38,39,
40,41,42,43,44,45,46,47,48,49,
50,51,52,53,54,55,56,57,58,59,
60,61,62,63,64,
]
}
impl_for_arrays!{
ty=u32,
len[
0,1,2,3,4,5,6,7,8,9,
10,11,12,13,14,15,16,17,18,19,
20,21,22,23,24,25,26,27,28,29,
30,31,32,33,34,35,36,37,38,39,
40,41,42,43,44,45,46,47,48,
]
}
impl_for_arrays!{
ty=u64,
len[
0,1,2,3,4,5,6,7,8,9,
10,11,12,13,14,15,16,17,18,19,
20,21,22,23,24,
]
}
impl_for_arrays!{
ty=usize,
len[
0,1,2,3,4,5,6,7,8,9,
10,11,12,13,14,15,16,17,18,19,
20,21,22,23,24,25,26,27,28,29,
30,31,32,33,34,35,36,37,38,39,
40,41,42,43,44,45,46,47,48,
]
}
macro_rules! declare_alignments {
(
$(( $docs:expr, $aligner:ident, $alignment:expr ),)*
) => (
$(
#[doc=$docs]
#[repr(C)]
#[repr(align($alignment))]
pub struct $aligner<Inline>(pub Inline);
unsafe impl<Inline> InlineStorage for $aligner<Inline>
where
Inline:InlineStorage,
{}
)*
)
}
pub mod alignment{
use super::*;
declare_alignments!{
( "Aligns its contents to an address at a multiple of 1 bytes.",AlignTo1,1 ),
( "Aligns its contents to an address at a multiple of 2 bytes.",AlignTo2,2 ),
( "Aligns its contents to an address at a multiple of 4 bytes.",AlignTo4,4 ),
( "Aligns its contents to an address at a multiple of 8 bytes.",AlignTo8,8 ),
( "Aligns its contents to an address at a multiple of 16 bytes.",AlignTo16,16 ),
( "Aligns its contents to an address at a multiple of 32 bytes.",AlignTo32,32 ),
( "Aligns its contents to an address at a multiple of 64 bytes.",AlignTo64,64 ),
( "Aligns its contents to an address at a multiple of 128 bytes.",AlignTo128,128 ),
}
#[repr(C)]
#[derive(Copy, Clone)]
#[cfg_attr(target_pointer_width="128",repr(C,align(16)))]
#[cfg_attr(target_pointer_width="64",repr(C,align(8)))]
#[cfg_attr(target_pointer_width="32",repr(C,align(4)))]
#[cfg_attr(target_pointer_width="16",repr(C,align(2)))]
pub struct AlignToUsize<Inline>(pub Inline);
unsafe impl<Inline> InlineStorage for AlignToUsize<Inline>
where
Inline:InlineStorage,
{}
}
#[repr(transparent)]
pub(crate) struct ScratchSpace<Inline>{
#[allow(dead_code)]
storage:std::mem::MaybeUninit<Inline>,
}
impl<Inline> ScratchSpace<Inline>{
#[inline]
#[allow(dead_code)]
pub(crate) fn new<T>(value:T)->Self
where
Inline:InlineStorage
{
Self::assert_fits_within_storage::<T>();
unsafe{
Self::new_unchecked(value)
}
}
#[inline]
#[allow(dead_code)]
pub(crate) unsafe fn new_unchecked<T>(value:T)->Self{
let mut this=Self::uninit_unbounded();
(&mut this as *mut Self as *mut T).write(value);
this
}
#[inline]
pub(crate) fn uninit()->Self
where
Inline:InlineStorage
{
unsafe{
Self::uninit_unbounded()
}
}
fn assert_fits_within_storage<T>(){
let align_val=std::mem::align_of::<T>();
let align_storage=std::mem::align_of::<Inline>();
assert!(
align_val <= align_storage,
"The alignment of the storage is lower than the value:\n\t{} < {}",
align_storage,align_val,
);
let size_val=std::mem::size_of::<T>();
let size_storage=std::mem::size_of::<Inline>();
assert!(
size_val <= size_storage,
"The size of the storage is smaller than the value:\n\t{} < {}",
size_storage,size_val,
);
}
}
impl<Inline> ScratchSpace<Inline>{
#[inline]
pub(crate) unsafe fn uninit_unbounded()->Self{
unsafe{
Self{
storage:std::mem::MaybeUninit::uninit()
}
}
}
}